1. Field of the Invention
This invention relates to automatic performance devices which automatically perform a piece of music on the basis of information on a note input thereto.
2. Description of the Related art
An automatic performance device is conventionally proposed which automatically performs a piece of music on the basis of music information input externally thereto.
In such a conventional automatic performance device, two processes are used for inputting information on a piece of music to be performed automatically. First is a real time inputting process and a step time inputting process.
In the real time inputting process, a musical scale and note length which the user inputs by performance using a performance operator such as a keyboard are detected as information on a piece of music to be automatically performed.
In the step time inputting process, inputting operators such as a musical scale inputting key and a note length inputting key are used to thereby sequentially input information on notes constituting a piece of music to be performed automatically.
The music information input and detected by the above method is stored in the order of its musical scale data, note length data, tone generation interval (gate time) data and tone intensity (velocity) data in a memory for each note and is read out from the memory to produce a note tone for automatic performance.
In such a conventional automatic performance device, and especially in an automatic performance device which inputs music information on a real time basis, the user uses a performance operator such as a keyboard to perform a piece of music to be performed automatically to thereby sequentially input music information. The user, however, cannot accurately input the note information, particularly, the note length, constituting the piece of music. If he wants to output a score of a piece of music performed automatically on the basis of such inaccurate note information, the output score itself would be undesirably inaccurate.
For example, if the note length of a quarter note is prescribed as 48, a note having a note length of 48 is a quarter note. Usually, in a score display, the length of a note is determined accurately to some extent even if there is also somewhat of an error involved in the length of the note in the past. For example, even if a note length of 49 or 47 is performed when a note of 48 is to be properly performed, in order to perform a quarter note, the automatic performance device determines that the note length to be performed is a quarter note and can output a scale of a quarter note.
When note information is input actually in the real time inputting process, a human being uses a keyboard or the like to perform a piece of music so that the note length would be 55 or 40 even if he intends to perform a correct quarter note. As just described, there is a great deviation between a predetermined note length and the actually input note length. Thus, note length cannot accurately be determined and a wrong score would be output in the score outputting process.
Since a musical scale, etc., constituting a piece of music to be performed automatically are sequentially input using an input operator such as a musical scale input key or a note length input key in an automatic performance device which uses the step inputting method, information on notes which constitute a piece of music is input accurately and, if a piece of music is to be displayed as a score on the basis of the input note information or to be output for recording purposes, an accurate score will be output.
Since music information stored in a memory is very accurate, however, there is the problem that automatic performance on the basis of the music information would bring about the performance of a piece of music in a mechanical sense, which is unnatural and fails in musicality.
That is, in an actual performance as a piece of music, the tempo is not constant the music itself, and the note length is not necessarily performed only in the length determined for that note. In addition, the tempo and note lengths of the same kind are not constant through the whole music and would sway slightly. Such a sway also changes depending on the performer. This change is expressed as the personality of the performer and is one factor indicative of the musicality of a piece of music. In an automatic performance device using a conventional step inputting process, data on such a sway cannot be input to the device. Notes of the same kind are performed accurately in the same length at all times, but such performance is unnatural and fails in musicality.
As just described above, the conventional automatic performance devices using the real time and step time inputting processes have problems contradictory to each other.